WO2010148281A2 - Procédé et appareil pour effacement en bloc dans un système de stockage holographique - Google Patents

Procédé et appareil pour effacement en bloc dans un système de stockage holographique Download PDF

Info

Publication number
WO2010148281A2
WO2010148281A2 PCT/US2010/039129 US2010039129W WO2010148281A2 WO 2010148281 A2 WO2010148281 A2 WO 2010148281A2 US 2010039129 W US2010039129 W US 2010039129W WO 2010148281 A2 WO2010148281 A2 WO 2010148281A2
Authority
WO
WIPO (PCT)
Prior art keywords
laser
photorefractive crystal
data
micro
pages
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US2010/039129
Other languages
English (en)
Other versions
WO2010148281A3 (fr
Inventor
Glenn A. Gladney
Marvin Hutt
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of WO2010148281A2 publication Critical patent/WO2010148281A2/fr
Publication of WO2010148281A3 publication Critical patent/WO2010148281A3/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/04—Processes or apparatus for producing holograms
    • G03H1/18—Particular processing of hologram record carriers, e.g. for obtaining blazed holograms
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/004—Recording, reproducing or erasing methods; Read, write or erase circuits therefor
    • G11B7/006—Overwriting
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/004—Recording, reproducing or erasing methods; Read, write or erase circuits therefor
    • G11B7/0065—Recording, reproducing or erasing by using optical interference patterns, e.g. holograms
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
    • G11B7/125—Optical beam sources therefor, e.g. laser control circuitry specially adapted for optical storage devices; Modulators, e.g. means for controlling the size or intensity of optical spots or optical traces
    • G11B7/127—Lasers; Multiple laser arrays
    • G11B7/1275—Two or more lasers having different wavelengths
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
    • G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
    • G11B7/1362—Mirrors
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
    • G11B7/2403—Layers; Shape, structure or physical properties thereof
    • G11B7/24035—Recording layers
    • G11B7/24044—Recording layers for storing optical interference patterns, e.g. holograms; for storing data in three dimensions [3D], e.g. volume storage
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/02—Details of features involved during the holographic process; Replication of holograms without interference recording
    • G03H2001/026—Recording materials or recording processes
    • G03H2001/0268—Inorganic recording material, e.g. photorefractive crystal [PRC]
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/04—Processes or apparatus for producing holograms
    • G03H1/18—Particular processing of hologram record carriers, e.g. for obtaining blazed holograms
    • G03H1/182—Post-exposure processing, e.g. latensification
    • G03H2001/183—Erasing the holographic information
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/04—Processes or apparatus for producing holograms
    • G03H1/18—Particular processing of hologram record carriers, e.g. for obtaining blazed holograms
    • G03H1/182—Post-exposure processing, e.g. latensification
    • G03H2001/183—Erasing the holographic information
    • G03H2001/184—Partially erasing
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
    • G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
    • G11B7/1372—Lenses
    • G11B2007/13727—Compound lenses, i.e. two or more lenses co-operating to perform a function, e.g. compound objective lens including a solid immersion lens, positive and negative lenses either bonded together or with adjustable spacing

Definitions

  • the present invention relates to holography.
  • the present invention is directed to a method and apparatus for bulk erasure in a holographic storage system.
  • Holographic techniques for storing images are well known. Such techniques are commonly used to store images in a variety of different applications.
  • Holographic memory is a prospective technology for massive data storage, with the unique advantages of high storage density, fast read/write rate, non-volatility, and no moving parts.
  • holographic memory technology may be capable of storing hundreds of billions of bytes of data, transferring them at a rate of a billion or more of bits per second and selecting a randomly chosen data element in 100 microseconds or less.
  • DRAM Dynamic Random Access Memory
  • SRAM Static Random Access Memory
  • EEPROM Electrically Erasable Programmable Read Only Memory
  • FLASH memory FLASH memory is nonvolatile and has read/write capability but it too has less storage capacity.
  • holographic memory may be used. Holographic memory stores information beneath the surface of the recording medium and uses the volume of the recording medium for storage. To date, holographic memory systems have been limited with respect to speed due to the need for re-encoding data and/or reading the data from the storage medium.
  • One way to bulk erase a holographic storage device is to temperature bulk erase. This is accomplished by removing the crystal from MUHCS storage device and placing the crystal in a dielectric holder. It is then inserted into a convection oven and the temperature is set to 200 ° C for two hours. While this method may achieve erasure of the photorefractive crystal, it is not a timely or procedurally simple.
  • An object of the invention may be a holographic storage system having bulk erasure.
  • Yet another object of the invention may be a method of bulk erasing in holographic storage system using a laser.
  • An aspect of this invention may be a holographic storage system with bulk erasing comprising: a photorefractive crystal for storing and retrieving a plurality of pages; a first laser for providing a reference beam and a data beam for storing the plurality of pages on a photorefractive crystal; and a second laser for bulk erasing the plurality of pages.
  • Another aspect of the invention may be a method of bulk erasure in a holographic storage system comprising: providing a first laser; a photorefractive crystal; and a second laser; storing a plurality of pages with the first laser on the photorefractive crystal; illuminating the photorefractive crystal with the second laser, wherein the illumination bulk erases the plurality of pages.
  • Still yet another aspect of the invention may be a holographic storage system with bulk erasing comprising: a photorefractive crystal for storing and retrieving a plurality of pages; a first laser for providing a reference beam and a data beam for storing the plurality of pages on a photorefractive crystal; and a second laser for bulk erasing the plurality of pages; a digital micro-mirror device for reflecting the data beam; a Micro-Electro-Mechanical Systems angle generating optical assembly for angle-multiplexing the reference beam; a camera for reading out the plurality of pages; and wherein a plurality of pages on the photorefractive crystal are removed after operation of the second laser.
  • FIG. 1 shov/s a schematic diagram of a holographic storage system using a one quadrant dual-axis MEMS mirror, in accordance with an embodiment of the invention.
  • FIG. 2 shows a schematic diagram of a holographic storage system using a four quadrant dual-axis MEMS mirror, in accordance with an embodiment of the invention.
  • FIG. 3 shows a one quadrant dual-axis MEMS mirror used in the holographic storage system shown in FIG. 1.
  • FIG. 4 shows a four quadrant dual-axis MEMS mirror used in the holographic storage system shown in FIG. 2.
  • FIG. 5 shows a MEMS mirror assembly used in the holographic storage system shown in FIGS. 1 and 2.
  • FIGS. 6-10 are graphical depictions of the photorefractive bit data recording mechanism.
  • FIG. 11 is a diagram of the holographic data recording and erasure.
  • FIG. 12 is a diagram of the holographic data readout.
  • FIG. 13 is a diagram showing holographic erasure.
  • FIG. 14 shows the controller logic of the holographic storage system.
  • FIG. 15 shows the method for writing to and the erasing of the photorefractive crystal.
  • FIG 16 is 3 close un view of the area where the reference and data beams im p act the photorefractive crystal.
  • FIG. 17 shows a close up view of the backside of a micro-mirror.
  • FIG. 18 shows the method for writing to the photorefractive crystal.
  • FIGS. 1 and 2 show holographic storage systems 100 and 200 respectively. All like numbered elements perform the same function throughout the Application and with the holographic storage systems 100 and 200. All references to and discussions of holographic storage system 100 also applies to the holographic storage system 200. The only differences between the two systems are noted in the body of the specification below and shown in the drawings which accompany this application.
  • the holographic storage system 100 comprises components placed on a board 5 and that uses a doped photorefractive crystal 22, which may be doped with iron.
  • the photorefractive crystal 22 may be illuminated by two laser beams, a data beam 9 and reference beam 6.
  • the data beam 9 and the reference beam 6 are generated by a laser 10.
  • the photorefractive crystal 22 is then referenced so as to form a holographic data page 40 in the photorefractive crystal 22.
  • the holographic storage system 100 of the present invention has demonstrated a potential for achieving 1.3 TeraByte data storage in a single volumetric storage media with access speeds in excess of 1 Gigabit per second.
  • a feature of the holographic storage system 100 is a angle-generating optical assembly 27.
  • the holographic storage system 100 comprises a laser 10.
  • the laser 10 shown in FIG. 1 is a frequency-doubled Neodymium laser producing continuous power output of 1.1 Watts at a wavelength of 532 nanometers with an optical coherence length of better than 1 meter, into a lowest-order Gaussian TEM transverse mode beam.
  • a semiconductor laser source may achieve similar results.
  • the holographic storage system 100 may further comprise external linear polarizers 12a, 12b and 12c.
  • the external linear polarizers 12a- 12c improve the contrast ratio of approximately 100:1 of the original beam 3 coming directly from the laser 10 to a value of approximately 10,000: 1. This renders the polarized light defined as horizontal with respect to the plane of the entire holographic storage system 100.
  • the holographic storage system 100 may also comprises a beam filter 16.
  • the beam filter 16 removes unwanted diffraction effects from the original beam 3 from the laser 10.
  • the holographic storage system 100 may also comprise a variable beam expanding telescope 18.
  • the variable beam expanding telescope 18 determines the size of the laser beam as it passes through the rest of the holographic storage system 100.
  • the holographic storage system 100 may also comprise plane mirrors 17a, 17b, 17c and 17d.
  • the plane mirrors 17a-17d redirect the laser beams at 90° angles.
  • the holographic storage system 100 may also comprise a special laser beam profile generator 20.
  • the laser beam profile generator 20 converts the fundamental Gaussian TEM 00 transverse mode beam emitted from the laser 10 into a plane wave output, within an overall tenth- wave accuracy.
  • the holographic storage system 100 may also comprise a beam expander 21 that in the present invention is used in reverse to render a horizontally polarized beam 4 that is now less than 3 millimeters in diameter.
  • the holographic storage system 100 may also comprise a beamsplitter 14.
  • the polarized beam 4 emitted by the beam expander 21 is reflected by the plane mirror 17b in order to direct the beam into the beamsplitter 14.
  • the beamsplitter 14 divides the beam 50/50 into two separate, horizontally polarized beams. Each of the two beams is directed into a pair of electro-optic modulators, 23a, 23b and through the linear polarizers 12b and 12c. The beams now form the data beam 9 and the reference beam 6.
  • the holographic storage system 100 may also comprise an up-collimating telescope 24, which takes the data beam 9 and directs it onto a data mirror assembly 26, which may be a spatial light modulator.
  • the data mirror assembly 26 will then direct the data beam 9 to the digital micro-mirror device 52.
  • digital micro-mirror device 52 may be a Texas Instruments Digital Micro-mirror Device MEMS type SXGA.95. This device contains the large array of micro-mirrors 25 that operate in a binary system to switch the data beam to individual "ON" or "OFF" signals that either reach the LiNbO 3 photorefractive crystal 22, discussed below.
  • FIG. 5 shows the data mirror assembly 50 which comprises the digital micro-mirror device 52.
  • the data mirror assembly 50 provides X-axis, Y-axis, Polar axis and Azimuthal axis adjustment and is driven by the assembly driver 54.
  • the holographic storage system 100 may also comprise a data projector 35.
  • the data projector 35 conditions the data beam 9 and projects it onto one face of the photorefractive crystal 22.
  • the holographic storage system 100 may also comprise an angle-generating optical assembly 27.
  • the reference beam 6 is transmitted from the beamsplitter 14 through the electro-optic modulator 23b and the linear polarizer 12b to the angle-generating optical assembly 27.
  • the angle-generating optical assembly 27 comprises a 45° optical assembly mirror 37, which further comprises feedback sensing in addition to two sub optical assembly mirrors 39a and 39b to limit the span of the MEMS micro-mirror 37 or 237.
  • the MEMS micro-mirror 237 is a four-quadrant MEMS type device with a single mirror driven by combs of electrostatic actuators.
  • a MirrorcleTechnology beam steering mirror capable of +/- 4.5 degrees in both "X" and "Y" axis directions of the reference beam 6.
  • the holographic storage system 100 may also comprise a reference beam steering device 33.
  • Reference beam steering device 33 is used to steer the reference beam 6 onto the photorefractive crystal 22 at 90° with respect to the direction of the data beam 9.
  • the holographic storage system 100 may also comprise a photorefractive crystal 22, which may be comprised OfLiNbO 3 and be placed in a housing.
  • a photorefractive crystal 22 which may be comprised OfLiNbO 3 and be placed in a housing.
  • Other materials for photorefractive crystals 22 that may be used are Lithium Tantalate (LiTaO 3 ), which is similar to Lithium Niobate, Barium Titanate (BaTiO 3 ); which has a different structure and does not work by the same mechanism, i.e. not photovoltaic; Potassium Tantalate Niobate (KTN) which is not as easily grown; Sodium Barium Niobate (SBN), and Barium Germanate Oxide (BGO).
  • LiTaO 3 Lithium Tantalate
  • KTN Potassium Tantalate Niobate
  • SBN Sodium Barium Niobate
  • BGO Barium Germanate Oxide
  • the holographic storage system 100 may also comprise a camera 28, which may be a Complementary metal-oxide-semiconductor (CMOS) array.
  • CMOS Complementary metal-oxide-semiconductor
  • the camera 28 is used to read out the holographically stored information when only the reference beam 6 is used and with the original data beam 9 switched off.
  • the holographic storages system 100 is connected to a controller 300 shown in FIG. 14 and discussed below.
  • the data page 40 is accessed using the camera 28 by using the encode/decode logic 314, which selects the page number and the cluster.
  • the page control logic 316 drives the micro-mirror 37 to the proper X and Y angles so that the selected data page 40 will be illuminated by the reference beam 6.
  • the angle- generating optical assembly 27 selects the rows where that cluster is stored and sends this information to the camera 28 as the Window.
  • a Read/Write pulse is generated which causes the photorefractive crystal 22 to be illuminated by the reference beam 6. While the photorefractive crystal 22 is being illuminated, the camera 28 issues a capture pulse which causes the camera 28 to capture the entire Page. The camera 28 downloads those rows specified by the window.
  • the embodiment shown uses the Cypress LUPA 1300-2. The 10- bit pixels are downloaded in 12 serial data streams with a sync channel. The camera 28 then aligns the pixels. The pixels are then fed into a threshold detector where they are first converted into bits and then concatenated into bytes. For the initial system, there are 2 levels and 1 bit.
  • the holographic storage system 100 may also comprise a camera 28, which may be a Complementary metal-oxide-semiconductor (CMOS) array.
  • CMOS Complementary metal-oxide-semiconductor
  • the holographic storage system 100 may also comprise a second laser 47 used only for bulk erasure of the entire photorefractive crystal 22.
  • the bulk erasure of the entire photorefractive crystal 22 removes all the data and involves the second laser 47 illuminating the photorefractive crystal 22 with unpolarized light at a range of divergence angles, which includes the whole range of address angles [-6° through +6° external to the crystal, both alpha and beta, 4.5°.
  • the second laser 47 may operate at the same wavelength as laser 10, which m the embodiments shown in FIGS. 1 and 2 operates at a wavelength of 532 nanometers.
  • the second laser 47 may operate at shorter wavelengths such as 350 nm to 550 nm.
  • the second laser 47 may be substituted by an incoherent light source. For example, a halogen light fed into fiber-optic bundles, can erase within an hour-strike from the erasure.
  • bulk erasure takes four hundred micro-seconds for each page.
  • Bulk erasure of an entire photorefractive crystal 22 may take up to 10 minutes depending upon the volume of the crystal 22.
  • Photorefractive crystals may be a 1 cm cube, 2 cm cube.
  • the term "bulk erasure” means substantially returning the photorefractive crystal 22 to a clean state, leaving no residual recorded data within the crystal. Bulk erasure therefore means all refractive index modulation ⁇ n has been reduced to zero, whereby trivalent Fe 3+ ions have been converted back into their original divalent Fe 2+ state within the LiNbO 3 crystal.
  • holograms may be formed.
  • the technique for forming holograms comprises splitting a highly coherent laser beam into two separate beams, namely the reference beam 6 and the data beam 9.
  • the reference beam 6 is directed onto the holographic storage medium, which is a photorefractive crystal 22, while the data beam 9 is directed onto the object whose image is to be stored.
  • Light from the object is directed to the photorefractive crystal 22 wherein an interference pattern is created owing to the interaction of the reference beam 6 with the light of the data beam 9.
  • the data beam 9 is typically reflected from a digital micro-mirroi device 52, which may be a spatial light modulator, (for example: Texas Instrument- Digital Mirror Device, DMD) that transports the information to be imaged and directs it to the photorefractive crystal 22 material.
  • a digital micro-mirroi device 52 which may be a spatial light modulator, (for example: Texas Instrument- Digital Mirror Device, DMD) that transports the information to be imaged and directs it to the photorefractive crystal 22 material.
  • DMD Texas Instrument- Digital Mirror Device
  • FIGS. 6-10 are graphical depictions of the photorefractive bit data recording mechanism.
  • FIGS. 6-10 depict how the data is recorded on the photorefractive crystal 22.
  • FIG. 6 shows laser spot for one bit incident on the photorefractive crystal 22.
  • FIG. 7 shows nhoto-ionization, the laser excites electrons in s n ot vicinitv b v ⁇ hoton absor p tion Excited electrons are re-trapped at vacant donor sites after movement in the conduction band.
  • FIG. 8 shows that electron movement causes non-uniform distribution of charge.
  • FIG. 9 shows that a non-uniform electric field is formed by the charge distribution.
  • FIG. 10 shows that the electric field distribution modulates the local refractive index by the Pockels effect.
  • FIGS. 11-13 are diagrams of the holographic data recording, erasure and readout. Data is shown in a simplified 4 X 4 array. Each pixel may have 1, 4 or 8 levels of gray scale. The phase of the interferometric hologram for each pixel is indicated by the direction of the cross-hatching in the pixel box.
  • the holographic storage systems 100 and 200 record multiple pages of data by angle multiplexing the reference beam 6 through a dual-angle mirror select.
  • various pages of data may be stored in the same volume region of the photorefractive crystal 22.
  • the reference beam 6 is projected onto the photorefractive crystal 22 at exactly the same angle that was used to store that page of data.
  • the reference beam 6 is diffracted by the photorefractive crystal 22 thereby allowing the recreation of the page that was stored at the particular location.
  • the re-created page may then be projected onto a charge-coupled device, such as a CMOS camera 28 that analyzes and forwards the data to a computer. If the reference beam 6 is not projected at exactly the same angle that was used for writing, the page to be retrieved may not be accessed.
  • the angle of the data beam 9 is not changed.
  • the data is transmitted on the data beam 9 by the digital mirror display 26 and digital micro-mirror device 52.
  • the doped photorefractive crystal 22 may be a LiNbO 3 crystal.
  • the data page 40 is read from the photorefractive crystal 22 by the camera 28, which takes the digital pattern of the photorefractive crystal 22 at a given data page 40 and imposes it on the camera 28, and mapping lens assembly 31.
  • a data page 40 of data is produced by the optical assembly micro-mirror 37 and will be recorded if the phase of the data beam 9 and the reference beam 6 are in a fixed phase relationship.
  • the phase coherence length of the laser beam must be longer than the difference in optical path lengths between the data beam 9 and reference beam 6 paths.
  • the fixed phase relationship between the data beam 9 and the reference beam 6 must be maintained at any angle/page designation.
  • the permissible optical phase shift error in the reference beam 6 at any angle must be significantly less than one fiftieth of a wavelength.
  • the controller 300 shown in FIG. 14 applies voltages to the first and second electro-optic modulators 23 a, 23b in order to control the writing and erasing to the photorefractive crystal 22.
  • the first electro-optic modulator 23a modulates the phase of the data beam 9
  • the second electro-optic modulator 23b modulates the reference beam 6.
  • step 102 there is no voltage applied to the first electro-optic modulator 23a and the second electro-optic modulator 23b.
  • step 104 a plus half- wave voltage is applied simultaneously to both the first electro-optic modulator 23a and the second electro-optic modulator 23b. This produces the necessary phase shift that enables both to operate as open shutter and enable writing and re-writing to the photorefractive crystal 22.
  • step 106 the second electro-optic modulator 23b that modulates the reference beam 6 is operated at a reversed (minus) half- wave voltage that is equal but opposite in polarity to how it is used for the writing function in step 104.
  • step 106 the phase of the reference beam 6 is shifted by 180° for the erase function while the data beam 9 is kept operating at its original plus half-wave voltage.
  • step 108 a plus hali-wave voltage is applied simultaneously to both the first electro-optic modulator 23 a and the second electro-optic modulator 23b. This produces the necessary phase shift that enables both to operate as open shutters and enable re-writing to the photorefractive crystal 22 and achieves the same state as that achieved in step 104.
  • the same erase function referred to in step 106, is also enabled if the voltage applied to the second electro-optic modulator 23b preserves its original plus polarity but is increased to plus three times the half-wave voltage used for a write sequence.
  • the second electro-optic modulator 23b used in this alternative manner for the erase function must be able to handle three times the applied half- wave voltage. It should be understood that the steps provided above may be performed in any sequence depending upon the needs of the user of the holographic storage system.
  • the first and second electro-optic modulators 23a and 23b act as high speed shutters in both the write and erase process. This feature allows them to be used together to control the time duration for either data writing or erasure while keeping the laser power at a fixed level.
  • Beam steering may be accomplished by using an angle generating optical assembly 27 which uses micro-electro-mechanical system (MEMS) angular multiplexing for holographic application.
  • MEMS micro-electro-mechanical system
  • angle-multiplexing generally involves maintaining a constant angle for the data beam 9 with respect to a first axis A of the photorefractive crystal 22. This is shown by the angle ⁇ and is typically 90° with respect to one input face of the photorefractive crystal, while varying the angle of the reference beam 6 with respect to its axis B lying at 90° with respect to axis A.
  • the angle of the reference beam 6 is varied with respect to axis B by two separate, orthogonal angles ⁇ and ⁇ , directed along a pair of planes X and Y determined by the two independent motions of the beam steering mirror.
  • FIG 16 Also shown in Figure 16 is the position of the C-axis of the photorefractive LiNbO 3 crystal which lies at 45° with respect to axis A, while both of these axes lie within the plane parallel to the direction of polarization of light for both object and reference beams.
  • the data page 40 is stored in 3D as opposed to 2D. Angle-multiplexing thereby allows a large number of holograms to be stored within a common volume of photorefractive crystal 22, thereby greatly enhancing the storage density thereof.
  • FIG. 16 is a close up view of the area in which the data beam 9 and reference beam 6 strike the photorefractive crystal 22 and more clearly shows the axes A-C and the respective angles by which the reference beam 6 is moved.
  • the orientation of the LiNbO3 photorefractive crystal 22 with its C-axis as shown lies at 45° with respect to the faces where the data beam 9 and reference beam 6 enter.
  • the Pockels effect may be represented by a second-rank tensor, which in turn may be represented in what is called “reduced matrix” form. There are two terms in the Pockels effect that can result in a "permanent" change in refractive index responsible for holographic data storage, namely rl3 and r33.
  • the selected orientation means the polarized light has only an extraordinary component tilted at 45° with respect to the C-axis.
  • extraordinary rays do not obey Snell's Law of refraction. Because of this slight distortions may occur at the corners of the volume storage region in the LiNbC ⁇ photorefractive crystal 11.
  • the holographic storage system 100 makes use of the commercially available Mirrorcle Technology Gimbal-less design ultra-fast two-axis laser angle generating optical assembly 27 which was developed for several non-holographic applications, including projection displays for vector-graphic projection, 3D Scanning, biomedical imaging and laser engraving.
  • the use of the angle generating optical assembly 27 device for holographic applications as discussed herein has several advantages.
  • the angle generating optical assembly 27 comprises micro-minor 37 and tuning mirrors 39a and 39b.
  • the Gimbai-less design permits ultra-fast two-axis laser beam steering that will scan within ⁇ 6 degrees of deflection along two orthogonal directions and settle to within 0.1 percent of full deflection in less than 200 microseconds. This facilitates read/write speeds in the gigabit/sec ranges; the two axis scanning provide complete access to the volume of the photorefractive crystal 22 thereby increasing storage capacity.
  • the angle generating optical assembly 27 is small enough to allow future integration into small form factor for general holographic memory systems.
  • the angle generating optical assembly 27 also has a feedback feature to determine its position and to control its motion.
  • Angle generating optical micro-mirror 37 is a MEMS beam steering mirror.
  • the reference beam 6 reflects off its front face.
  • a semiconductor laser 91 may be located behind the micro-mirror 37 and may direct its own output beam onto the back side 92 of micro-mirror 37 through a small hole 93 provided for that purpose.
  • the separate semiconductor diode laser 91 used in this feedback arrangement is situated at an angle ⁇ of 30° with respect to a line D intersecting the small hole 93.
  • the light reflected from the back side 92 of the MEMS micro-mirror 37 is directed in three dimensions onto a quadrant Position Sensing Diode (PSD).
  • PSD Position Sensing Diode
  • Output from the PSD is fed back into the page control logic 316 in the controller 300 which contains a Proportional-Integral -Derivative (PID) controller.
  • PID Proportional-Integral -Derivative
  • the angle generating optical assembly 27 requires several orders of magnitude less driving power. Continuous full-speed operation of electro-static actuators help to dissipate less than a few
  • the optical performance of the angle generating optical assembly 27 must be sufficient so as not to degrade the overall quality of the stored hologram. In general an angle generating optical assembly 27 that achieves the largest angle and the highest operating speed is desirable. In addition, the aperture size and quality are also very important parameters. In order to maximize resolution and to avoid clipping of the beam, usage of larger mirrors is preferred.
  • the micro-mirror 37 may have a diameter of 1.1 millimeters or less. The larger the diameter of the micro-mirror 37, the slower it will be. However, as the micro-mirror 37 is enlarged the inertia of the mirror is increased and for a given spring stiffness the resonant frequency will decrease, thus, reducing speed.
  • the micro-mirror 37 must have good reflectivity in the visible and near infrared ranges; this requires either metallization or a dielectric mirror.
  • the micro-mirror 37 surface should be sufficiently flat as to not distort the beam and must also have surface roughness less than lOOnm at a minimum.
  • the angle generating optical assembly 27 is operated in a point-to-point optical beam scanning mode to achieve unique resolvable angles.
  • a steady-state analog actuation voltage results in a steady-stage analog angle of rotation of the micro-mirror.
  • the one-to-one correspondent actuation voltages and resulting angles are highly repeatable with no degradation over time.
  • Positional precision of the micro-mirrors 37 is at least 14 bits, i.e. within 0.2 milli-degrees.
  • a sequence of actuation voltages that are properly conditioned results in a sequence of angles for point-to-point scanning.
  • the accuracy of the system 100 is such that it is possible to achieve more than 10 million angles with each angle characteristic of a data page 40.
  • the angle generating optical assembly 27 may also be operated over a very wide bandwidth from dc to several kilohertz.
  • Angle generating optical assembly 27 with 0.8 mm diameter-sized micro-mirrors 37 are used to achieve angular beam scanning of up to 500 rad/s with first resonant frequency in both axes above 4 kHz.
  • Large angle step response settling times of ⁇ 1OO ⁇ s have been demonstrated on devices with micro-mirrors up to 0.8 mm in diameter.
  • Such fast and broadband operation allows data storage and retrieval to be very effective for holographic applications.
  • Alignment of the micro-mirror 37 of the angle generating optical assembly 27 requires mounting the angle generating optical assembly 27on a complex positioning system 36.
  • the positioning system 36 is a 6 axis translational stage that allows the angle generating optical assembly 27 to move up-down, left-right and in-out.
  • the diameter of the beam impinging upon the angle generating optical assembly 27, must be smaller than the diameter of the micro-mirror 37.
  • the beam diameter is in the order of .5 mm, less than 2/3 ld the mirror size. This is important to avoid run-off from the angle generating optical assembly 27.
  • the holographic memory technology enables high-density and high-speed holographic data storage with random access during data recording and readout.
  • An embodiment of the invention utilizes the angle generating optical assembly 27, which is a MEMS (Micro-Electro-Mechanical Systems) beam steering device.
  • MEMS Micro-Electro-Mechanical Systems
  • the MEMS angle generating optical assembly 27 is the integration of mechanical elements, sensors, actuators, and electronics placed on a common silicon substrate through micro-fabrication technology.
  • the fabrication method for these micro-mirrors is similar (or identical) to that of a cantilever structure. While the electronics are fabricated using integrated circuit (IC) process sequences (e.g., CMOS, Bipolar, or BICMOS processes), the micromechanical components are fabricated using compatible "micromachining" processes that selectively etch away parts of the silicon wafer oi add new structural layers to form the mechanical and electromechanical devices MEMS angle generating optical assembly 27.
  • IC integrated circuit
  • the MEMS angle generating optical assembly 27 has a micro-mirror 37 that may scan a reference beam 6, which is split from a single collimated laser beam, along a horizontal plane in parallel with the Z axis of the LiNbO 3 photorefractive crystal 7. Further, the micro-minor 37 of the MEMS angle generating optical assembly 27 may be varied by small increments with respect to each new data page 40 so as to specifically orient the reference beam 6 to the photorefractive crystal 22 in an angular multiplexing scheme. Therefore, the micro-mirrors 37 and 237 of the MEMS angle generating optical assembly 27 in this invention are utilized for beam steering in the holographic storage systems 100 and 200.
  • the holographic storage systems 100 and 200 use a Write Control Logic 310 in the storing of data to the photorefractive crystal 22.
  • the logic used in the recording, reading and erasure of the photorefractive crystal 22 is shown in FIG. 14 as placed on the controller 300.
  • Two versions of the Write Control Logic 310 may be used for the digital micro-mirror device 52, one for the Indirectly Modulated Spatial Light Modulator (IM-SLM) and one for the Directly Modulated Spatial Light Modulator (DM-SLM).
  • IM-SLM Indirectly Modulated Spatial Light Modulator
  • DM-SLM Directly Modulated Spatial Light Modulator
  • the IM-SLM consists oi an array ol SLM micro-mirrors 25 as part ol the data mirror assembly.
  • Each SLM micro-mirror 25 is individually controlled and represents one unique data point per page.
  • the SLM micro-mirrors 25 are switched between two positions, one which reflects the data beam into the photorefractive crystal 22, hereinafter referred to as the ON position and one which reflects the data beam 9 away from the photorefractive crystal 22, hereinafter referred to as the OFF position.
  • the reflected light from that SLM micro-rnirror 25 combines with the reflected light in the photorefractive crystal 22, it combines with the reference beam 6 to write a pixel into the photorefractive crystal 22.
  • the intensity of the pixel is determined by the amount of time that the SLM micro-minor 25 is in the ON position.
  • the Write Control Logic 310 sets the SLM micro-minors 25 in the sector to be written to the ON position.
  • the Write Control Logic 310 may then command the Erase Module 312 to erase this sector in one of the manners described above.
  • the Write Control Module 310 then sets the pixels of the SLM micro-mirrors 25 corresponding to the pixels that are to be written to the ON position.
  • the first electro-optic modulator 23a is opened and the sector in written to.
  • the step of setting the SLM micro-mirrors 25 in the sector to be written to the ON position is repeated several times as follows:
  • FIG. 18, is the method for writing to the photorefractive crystal 22 shown.
  • step 202 the SLM micro-mirrors 25 for all of the pixels to be illuminated are put in the ON position and the first electro-optic modulator 23a is opened and shut.
  • step 204 the SLM micro-minors 25 for the pixels that are to have the lowest level of grayscale are turned to the OFF position and step 202 is repeated.
  • the SLM micro-mirrors 25 for the pixels that are to have the next lowest level of grayscale are turned to the OFF position and the previous step 202 is repeated.
  • DM-DSLM also uses a Write Control Logic 310.
  • the holographic data storage system 100 of the present invention also has an Encode/Decode Logic 314 .
  • the Encode/Decode Logic 314 may be located within the controller 300, which may be an embedded processor.
  • the Encode/Decode Logic 314 converts the most significant portion of the address field of the read or write command received from the system interface to the appropriate angles sent to the Page Control Logic 316.
  • the Encode/Decode Logic 314 selects which sector will be written to or read from the photorefractive crystal 22.
  • Reading occurs by blocking the data beam 9 and projecting onto the material the reference beam 6 at the page angle used during writing that page. This is achieved by applying the corresponding voltages for the x-axis and y-axis directions for that particular page.
  • the mirror digital micro-mirror device 52 itself does not have to be rotated, it has the potential for faster read time, higher fidelity and no moving parts.
  • the holographic storage system 100 may suffer from high speed data manipulation.
  • a very precise algorithm must be used for read and write operations. For example, one must initiate specific commands such as: not read/write at the same location at the same time, and with the OFF states blocked. This requires prioritizing read/write sequences and therefore implies arbitration and memory location lock.
  • the present invention provides for the use of MEMS (Micro- electro-mechanical Systems) mirror technology for high-speed beam steering in a compact holographic system.
  • MEMS Micro- electro-mechanical Systems
  • One or more embodiments of the invention may also make use of digital micro- mirror device 52, which is used frequently as a spatial light modulator. Due to its superior switching speed, contrast ratio, and overall maturity, a digital micro-mirror device 52 is useful for holographic media. Digital micro-mirror device 52 can be used in a static mode for highspeed beam steering. The selection of a SLM micro-mirror 25 from the array of mirrors in the holographic storage system 100 that uses digital micro-mirror device 52, can provide a means for the reference beam 6 to address a specific location in the photorefractive crystal 22.
  • the Erase Logic 312 changes the phase of the reference beam 6. It can use either a first or second electro-optic modulator 23a and 23b on the data or on the reference path. In this situation the first and second electro-optic modulator 23a and 23b are half wave phase shifters With Beam Steering Control 318, the controller 300 converts the address from the read or write command from the system interface to an X axis and a Y axis angle.
  • Beam Steering Control 318 There are two forms of Beam Steering Control 318, one for angle generating optical assembly 27 and one for acousto-optical beam steering.
  • the beam steering interface converts the X and Y angles to numerical outputs to DACs.
  • the angle that the beam is deflected is proportional to the frequency of the driving voltage.
  • the Beam Steering Control 318 will output a square wave at the appropriate frequency.
  • Angle multiplexing may be summarized as follows, current art read and write pages are focused on resolvable spots generated by the angle generating optical assembly 27. Quality of the steering device is determined by the resolvable angles, small angles, hysteresis, switching and reflectivity.
  • the holographic data readout may be summarized as follows: the holographic storage system 100 and 200 permits independent retrieval of data pages.
  • the data beam 9 is turned off.
  • the reference beam 6 dual angle of incidence to the photorefractive crystal 22 is selected.
  • a reproduction of the holographic page is mapped onto PDA. The entire page may be read immediately and the selected data is retrieved from the page.
  • noise can corrupt information gathered when reading data on a given page.
  • This noise may be divided into two types: systematic noise due to photorefractive crystal defects, magnification defects between mirror array and detector array and other focusing defects; or random noise due to speckle, interpixel noise, interpag ⁇ crosstalk, detector shot noise, thermal noise and unwanted scattered light.
  • systematic noise can be filtered or compensated
  • random noise will set limits on holographic reading precision which are addressed by specifying required diffraction efficiency ⁇ to achieve a given signal- to-noise ratio SNR, on readout at a specified rate for a specified bit error rate BER.
  • an error correction code ECC is also introduced into the encoding/decoding method used.

Landscapes

  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • General Physics & Mathematics (AREA)
  • Holo Graphy (AREA)

Abstract

La présente invention concerne un procédé et un système pour l'effacement en bloc dans un système de stockage holographique. Le procédé consiste à éclairer tout le volume de la zone de stockage d'un cristal photoréfractif avec un laser de manière à permettre l'effacement en bloc, ou il peut consister à effacer sélectivement une portion d'une page écrite unique. Pour l'effacement en bloc de l'ensemble du cristal photoréfractif, on utilise un laser distinct ou une source de lumière incohérente.
PCT/US2010/039129 2009-06-18 2010-06-18 Procédé et appareil pour effacement en bloc dans un système de stockage holographique Ceased WO2010148281A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US21822009P 2009-06-18 2009-06-18
US61/218,220 2009-06-18

Publications (2)

Publication Number Publication Date
WO2010148281A2 true WO2010148281A2 (fr) 2010-12-23
WO2010148281A3 WO2010148281A3 (fr) 2011-03-03

Family

ID=43354103

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2010/039129 Ceased WO2010148281A2 (fr) 2009-06-18 2010-06-18 Procédé et appareil pour effacement en bloc dans un système de stockage holographique

Country Status (2)

Country Link
US (1) US8045246B2 (fr)
WO (1) WO2010148281A2 (fr)

Family Cites Families (58)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3703328A (en) 1971-07-21 1972-11-21 Bell Telephone Labor Inc Devices utilizing improved linbo' holographic medium
US3799642A (en) 1973-03-27 1974-03-26 Rca Corp Holographic recording on photochromic lithium niobate
JPS544856B2 (fr) 1974-01-17 1979-03-10
US3873179A (en) 1974-06-10 1975-03-25 Rca Corp Lithium niobate hologram readout using continuous incoherent noise erasing light
FR2346810A1 (fr) 1976-03-30 1977-10-28 Thomson Csf Dispositif optique de stockage multiplie en volume
JPS54103055A (en) 1978-01-31 1979-08-14 Nippon Telegr & Teleph Corp <Ntt> Spectrometer
US4750153A (en) 1985-10-11 1988-06-07 Hughes Aircraft Company Associative holographic memory apparatus employing phase conjugate mirrors and a two-wave mixing contra-directional coherent image amplifier
US5132811A (en) 1989-08-10 1992-07-21 Seiko Instruments Inc. Holographic operating optical apparatus
US5493628A (en) * 1991-10-17 1996-02-20 Lawandy; Nabil M. High density optically encoded information storage using second harmonic generation in silicate glasses
JP2804954B2 (ja) 1992-08-13 1998-09-30 日本電信電話株式会社 偏波無依存型光パルス分離回路および偏波無依存型光パルス多重回路
US5422873A (en) 1993-03-25 1995-06-06 California Institute Of Technology Multiplexing and selective updatable fixing and erasing of volume holograms in photorefractive media and second harmonic generation in photorefractive media by optically induced periodic poling
US6272095B1 (en) 1994-07-22 2001-08-07 California Institute Of Technology Apparatus and method for storing and/or reading data on an optical disk
US5450218A (en) 1994-08-04 1995-09-12 Board Of Trustees Of The Leland Stanford Junior University Method for encoding and decoding digital data in holographic storage media
US5550779A (en) 1994-10-20 1996-08-27 California Institute Of Technology Holographic memory with angle, spatial and out-of-plane multiplexing
EP0799537B1 (fr) 1994-12-23 2001-09-12 BRITISH TELECOMMUNICATIONS public limited company Noeud dans reseau de communication optique a multiplexage par repartition dans le temps
WO1996032666A1 (fr) 1995-04-12 1996-10-17 Northrop Grumman Corporation Procede d'attenuation de diaphonie dans des hologrammes a haut rendement
US5717508A (en) 1995-04-13 1998-02-10 Northrop Grumman Corporation Method for dynamically refreshing angle-multiplexed holograms in photorefractive media
KR19990028735A (ko) * 1995-07-05 1999-04-15 모리슨 그랜트 광 저장 시스템
US6061154A (en) 1997-06-24 2000-05-09 Lucent Technologies, Inc. System and method for steering focal plane data to access data locations in a holographic memory
US6031643A (en) 1997-07-08 2000-02-29 International Business Machines Corporation Method for holographic storage
US6556531B1 (en) 1998-02-16 2003-04-29 Nippon Telegraph And Telephone Corporation Multi-layered holographic read-only memory and data retrieval method
JP3521113B2 (ja) 1998-03-27 2004-04-19 パイオニア株式会社 体積ホログラフィックメモリ光情報記録再生装置
JP3547610B2 (ja) 1998-03-27 2004-07-28 パイオニア株式会社 体積ホログラフィックメモリ光情報記録再生装置
KR100298392B1 (ko) 1998-05-28 2001-08-07 구자홍 홀로그래픽저장장치
JP3989627B2 (ja) 1998-06-23 2007-10-10 富士通株式会社 光ゲート装置、該装置の製造方法及び該装置を備えたシステム
US6023352A (en) 1998-08-11 2000-02-08 University Of Massachusetts Methods and systems for thermal fixing and/or erasing of holograms
JP2000155950A (ja) 1998-09-17 2000-06-06 Pioneer Electronic Corp 体積ホログラフィックメモリ、及びそれを利用した光情報記録再生装置
JP2000285457A (ja) 1999-03-30 2000-10-13 Pioneer Electronic Corp 体積ホログラフィックメモリ光情報記録再生装置
US6468699B2 (en) * 1999-05-14 2002-10-22 Adil Lahrichi Reversible hologram fixation in photorefractive materials using incoherent ultraviolet light
US6026053A (en) 1999-05-21 2000-02-15 The United States Of America As Represented By The Director Of The National Security Agency Photorefractive read-only optical memory apparatus using phase, frequency, and angular modulation
US6686097B2 (en) 1999-06-01 2004-02-03 Adil Lahrichi Reversible hologram fixation in photorefractive materials using incoherent ultraviolet light
JP3611756B2 (ja) 1999-08-31 2005-01-19 パイオニア株式会社 ホログラム記録装置及びその方法
JP3611757B2 (ja) 1999-08-31 2005-01-19 パイオニア株式会社 ２色ホログラム記録再生装置
GB9929953D0 (en) * 1999-12-17 2000-02-09 Cambridge Res & Innovation Holographic recording medium,and method of forming thereof,utilizing linearly polarized light
JP4454763B2 (ja) 2000-03-03 2010-04-21 富士通株式会社 信号光を波形整形するための方法、装置及びシステム
JP3948598B2 (ja) 2000-09-01 2007-07-25 富士通株式会社 光信号を処理するための方法、装置及びシステム
US6999397B2 (en) 2001-03-23 2006-02-14 Daewoo Electronics Corp. Holographic digital data storage system compatible with holographic and reflective medium
US7295356B2 (en) 2001-06-08 2007-11-13 Inphase Technologies, Inc. Method for improved holographic recording using beam apodization
US7095959B2 (en) 2001-06-20 2006-08-22 Evident Technologies Optical time division multiplexing/demultiplexing system
US7005669B1 (en) 2001-08-02 2006-02-28 Ultradots, Inc. Quantum dots, nanocomposite materials with quantum dots, devices with quantum dots, and related fabrication methods
US6819845B2 (en) 2001-08-02 2004-11-16 Ultradots, Inc. Optical devices with engineered nonlinear nanocomposite materials
JP4472222B2 (ja) 2001-09-28 2010-06-02 富士通株式会社 信号光を波形整形するための方法、装置及びシステム
JP2003131272A (ja) 2001-10-29 2003-05-08 Fujitsu Ltd 光信号処理装置、光デマルチプレクサ、波長変換装置、光信号処理方法及び波長変換方法
US7507504B2 (en) 2002-02-15 2009-03-24 University Of Massachusetts Optical storage system
JP4397567B2 (ja) 2002-07-05 2010-01-13 富士通株式会社 光ａｎｄゲート及び波形整形装置
US6859293B2 (en) 2002-10-22 2005-02-22 Zebra Imaging, Inc. Active digital hologram display
JP3896092B2 (ja) 2003-03-18 2007-03-22 株式会社東芝 光記録媒体
US7149014B2 (en) 2003-04-18 2006-12-12 California Institute Of Technology Holographic memory using beam steering
KR20040103115A (ko) 2003-05-31 2004-12-08 주식회사 대우일렉트로닉스 홀로그래픽 롬 시스템의 광 검출 장치
US6906838B2 (en) 2003-07-17 2005-06-14 Agilent Technologies, Inc. Systems and methods for routing optical beams along optical paths using steerable mirrors
US7245408B1 (en) 2003-10-10 2007-07-17 Zebra Imaging, Inc. Systems and methods for producing wide field-of-view holographic displays
JP2005173530A (ja) 2003-11-17 2005-06-30 Osaka Industrial Promotion Organization 光信号処理方法及び装置、非線形光ループミラーとその設計方法並びに光信号変換方法
WO2005078533A1 (fr) 2004-02-10 2005-08-25 Zebra Imaging, Inc. Depot de materiau photosensible d'enregistrement d'hologrammes numeriques
US7006742B2 (en) 2004-07-12 2006-02-28 The Furukawa Electric Co., Ltd. Highly nonlinear optical fiber and highly nonlinear optical fiber module
JPWO2006035722A1 (ja) 2004-09-29 2008-05-15 旭硝子株式会社 非線形ファイバ、波長変換方法および波長変換器
JP4649158B2 (ja) * 2004-09-30 2011-03-09 富士フイルム株式会社 ホログラム記録方法
US7187481B1 (en) * 2004-12-23 2007-03-06 Storage Technology Corporation System and method for providing gain and thresholding to a holographic data parallel recording and replication system incorporating independent angular address assignment
JP4605104B2 (ja) 2006-06-19 2011-01-05 富士ゼロックス株式会社 ホログラム再生方法及び装置

Also Published As

Publication number Publication date
US8045246B2 (en) 2011-10-25
US20100321749A1 (en) 2010-12-23
WO2010148281A3 (fr) 2011-03-03

Similar Documents

Publication Publication Date Title
US8605561B2 (en) Method and system for re-writing with a holographic storage medium
US20100322058A1 (en) Holographic storage system using angle-multiplexing
CN111033613B (zh) 用于在玻璃上快速写入数据的多光束光学系统
US10236027B1 (en) Data storage using light of spatially modulated phase and polarization
US6819469B1 (en) High-resolution spatial light modulator for 3-dimensional holographic display
US7457016B2 (en) Optical system for processing CD, DVD and holographic digital data
US6999397B2 (en) Holographic digital data storage system compatible with holographic and reflective medium
US7480085B2 (en) Operational mode performance of a holographic memory system
US7200097B2 (en) Parallel recording and reading of diffractive memory using multiple object beams
US6031643A (en) Method for holographic storage
US20100246367A1 (en) Optical information recording method and apparatus using the same
JP4059977B2 (ja) ３次元ホログラフィックデータ格納システム
US20020008889A1 (en) Holographic memory and optical information recording and reproducing apparatus using the same
US8045246B2 (en) Method and apparatus for bulk erasure in a holographic storage system
JP2012198987A (ja) 高密度、広帯域幅の多重ホログラフィックメモリ
US6181665B1 (en) Volume holographic data storage system
US6005693A (en) Method for holographic storage
US6900914B1 (en) Optical information recording and reproducing apparatus having volume holographic memory
CN101188127A (zh) 应用于光学存储系统的光束移动部件
JP2004362741A (ja) 駆動ミラーを用いるホログラフィック装置及びその方法
JPH0339774A (ja) 画像記録再生装置
US20060193024A1 (en) Double facing double storage capacity
US7202984B2 (en) Double faced double storage capacity medium
JP2006126642A (ja) ホログラムメモリ装置及びホログラムの消去方法。
KR100508387B1 (ko) 홀로그래픽 데이터 저장 및 재생 시스템과 이를 이용한데이터 재생방법

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 10790246

Country of ref document: EP

Kind code of ref document: A2

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 10790246

Country of ref document: EP

Kind code of ref document: A2